The United States has made it clear that it cannot accept Russia's demand for a legal guarantee with a set of "military-technical criteria" that could, in effect, create limitations on Washington's ability to develop and deploy future missile defense systems.

The U.S. stand on the controversial issue was explained by Special Envoy Ellen Tauscher while delivering remarks at the 10th Annual Missile Defense Conference in Washington, DC.

"They (Russia) want a piece of paper they can point to when a U.S. ship enters certain waters or when an interceptor has a certain speed. We certainly cannot accept limitations on where we deploy our Aegis ships. These are multi-mission ships that are used for a variety of missions around the world, not just for missile defense. We also will not accept limitations on the capabilities and numbers of our missile defense systems," Tauscher told the conference on Monday.

However, she said the U.S. "would be willing to agree to a political statement that our missile defenses are not directed at Russia." She reiterated the U.S. government's stand that "any statement will be politically binding and it would publicly proclaim our intent to cooperate and chart the direction for cooperation, not limitations.

"In order to reach the point where we can engage in genuine missile defense cooperation with Russia in ways that truly benefit U.S. national security, we may need to be more transparent and continue to build trust between our two nations. But at the same time, we would not give away hit to kill technology, telemetry, or any other types of information that would compromise our national security," she insisted.

"Missile defense is one area where we can work together with Russia to end Cold War thinking and move away from Mutually Assured Destruction toward Mutually Assured Stability.

"That means getting Russia inside the missile defense tent now, working alongside the U.S. and NATO, while we are in Phase 1," she said and reassured that NATO missile defense systems would not threaten Russia's strategic nuclear capabilities or strategic forces.

Instead, Tauscher assured that the ballistic missile threat from nations like Iran be reduced, "our missile defense system can adapt accordingly."

She said the U.S. had offered Russia an opportunity to view one of its Aegis SM-3 missile defense flight tests, but added that they were not proposing to provide them with classified information.

"Rather, we are offering for them to operate in international waters, giving them the time of launch of our target (which we provide to mariners and airmen as normal course). This will be a good first step in transparency measures with the Russian Federation, allowing them to see for themselves, what we are saying about our system is accurate," the U.S. envoy said.

She called upon Moscow to seize this opportunity sooner rather than later. "Confidence takes time to build. If Russia is truly concerned about Phases 3 and 4, it would be best for Russia to start cooperating as early as possible to better understand our capabilities as they evolve. We prefer future decision-making on this issue to be made according to on-the-ground realities, not worst-case guesses. We prefer letting data and facts inform our decision making, rather than lingering Cold War paranoia," Tauscher said.

She vowed that she would "keep working to see if we can come up with a plan for cooperation."

"Transforming missile defense from an issue of contention to one of cooperation will also help move us forward on the road toward greater nuclear reductions and, eventually, elimination," she added.

She concluded by reiterating that "our cooperation with Russia will not come at the expense of our plans to defend Europe from regional ballistic missile threats or for the defense of the U.S. homeland."